The present disclosure relates to an image forming apparatus employing an electro-photographic method, such as a copier, a printer, a facsimile machine, or a multifunction peripheral having functions of these.
In a conventional image forming apparatus employing an electro-photographic process, the following process is typically performed. A surface of an image carrier such as a photosensitive drum is uniformly charged by a charging device, then the surface of the image carrier is exposed to light (light irradiation) from an exposure device to form an electrostatic latent image on the image carrier, and then the thus formed electrostatic latent image is developed into a toner image by a developing device. A sheet (a recording medium) is conveyed from a registration roller pair in a manner coordinated with the timing of toner image formation, then the toner image is transferred onto the sheet passing through a transfer nip at which the photosensitive drum and a transfer roller contact each other, and then fixing processing is performed.
In the above-described configuration, in a case where a horizontal conveyance method is adopted in which sheets are conveyed in a horizontal direction, the developing device is located above a sheet conveyed from the registration roller pair to the photosensitive drum. This arrangement involves risk of a sheet becoming stained with toner leaked from the developing device.
To address this inconvenience, there have been proposed various methods for reducing the risk of stained sheets, and for example, there is known an image forming apparatus which includes a transfer guide member which restricts a position that a recording medium assumes while it is being conveyed toward a transfer position, and in which an air-flow guide member is provided in the transfer guide member to be opposite the image carrier, the air-flow guide guiding an air flow moving along the image carrier from a developing position to the transfer position to move in a direction away from the image carrier.
There is also known an image forming apparatus which includes a guide which is provided on a downstream side of a developing device but on an upstream side of a transfer roller to guide a sheet to between the transfer roller and a photosensitive drum, a fan which generates a second air flow which is different from a first air flow generated by rotation of the photosensitive drum and which passes below the guide, and a flow path which is provided on an upstream side of a sheet path through which a sheet passes but on the downstream side of the developing device, and which guides part of the first air flow to the second air flow.